The invention relates to a wellbore pipe protection device for protecting, in a condition mounted to a wellbore pipe end, the screw thread of the pipe end.
It is remarked that the term “wellbore pipe” as referred to in the present text is meant to comprise various types of pipes used in wellbore operations, both during drilling phases and during production phases. Hence, the term “wellbore pipe” comprises various types of drill, casing and tubing pipes used in wellbores.
Such protection devices serve to protect internal or outside screw threads of wellbore pipe ends against potential damage during transportation and storage of wellbore pipes. When wellbore pipes are in operation, i.e. when they are interconnected to form a pipe string, the protection devices have been removed from the pipe ends.
In practice, types of wellbore pipe protection devices are known, wherein the protection device has a substantially cylindrical body provided with screw thread for co-operation with the screw thread of a wellbore pipe. For a first class of these known devices, its cylindrical body has internal screw thread that matches the outside screw thread of the corresponding wellbore pipe end. For a second class of these known devices, its cylindrical body has outside screw thread that matches the internal screw thread of the corresponding wellbore pipe end. When installing known devices of the said type, an operator screws the devices onto/into the wellbore pipe ends. When de-installing these known devices, an operator manually unscrews the devices from the pipe ends.
A drawback of these known devices is, that the screwing and unscrewing of the protection devices relative to the wellbore pipes is a time consuming task. The reason is that the screwing and unscrewing involves relative movements over relatively long helical paths and with relatively high friction. Since wellbore operations typically require the handling of large numbers of wellbore pipes, the time consuming task of installing and de-installing the large numbers of protection devices has a negative influence on the speed of the operations and/or the related labour costs involved in the operations. Note, that wellbore operations normally take place in relatively unclean environments, which often leads to dirty screw threads of protection devices and of wellbore pipes. This further hampers the task of screwing and unscrewing of the protection devices.
In view of the abovementioned drawbacks, some other protection devices are known which other devices are not based upon screwing and unscrewing of such device relative to the pipe's screw thread to be protected.
U.S. Pat. No. 4,429,719A discloses a pipe thread protector according to the preamble of independent claim 1 appended to the present specification. This protector known from U.S. Pat. No. 4,429,719A has an inner member 12 and an outer member 11. In mounted condition of the protector, these inner and outer members may be interlocked relative to one another by means of a vacuum system. The vacuum system is manually controlled by means of a valve 21 which is manually retractable by means of a handle 34. Removing the protector from the pipe requires the successive steps of: manually retracting the handle for allowing the vacuum to be cancelled, manually pulling away the outer member from the pipe and manually pulling away the inner member from the pipe. Conversely, mounting the protector onto the pipe requires, firstly, the manual placement of the inner member and, secondly, the manual placement of the outer member. Each of such steps of pulling away and of placing of the inner member and of the outer member generally needs to be performed by two hands of an operator. All in all, removing and mounting this known pipe thread protector are still relatively time consuming. Since wellbore operations typically require the handling of large numbers of wellbore pipes, the time consuming task of installing and de-installing the large numbers of this known pipe thread protector has a negative influence on the speed of the operations and/or the related labour costs involved in the operations.
Another device for protecting threaded ends of pipes is known from U.S. Pat. No. 2,238,643A. This document discloses a protector for interior threads of pipe ends. This known protector comprises a frusto-conical cup 3 arranged in segments, a paper cup 12, as well as a coniform screw-threaded plug 16 extending through the bottom wall 5 of the cup 3 in screw-threaded engagement therewith. Installing and de-installing of this known protector require, amongst others, the continued screwing of the tapered screw-threaded plug 16, evidently by using a special tool.
Yet another device for protecting threaded ends of pipes is known from WO99/07978A1 (hereinafter “WO'978”). This known device has a cap member 15a having a covering sleeve 21 (see FIGS. 2A and 3A of WO'978). The cap member 15a may be fitted to the socketed end 12c of a pipe section 12 (see FIG. 1 of WO'978) by means of a tension means 16 (separately shown in FIG. 6 of WO'978). The tension means 16 comprises a stem 40 (see FIG. 2A of WO'978) with outwards facing threading cooperating with a corresponding inwards facing threading of a holder 17, which holder 17 is fixedly attached to the cap member 15a. The stem 40 is manually pivotable by means of a loose handgrip tool 45 (see FIGS. 10 and 11 of WO'978). Manual pivotation of the handgrip tool 45 results in movement of a wedge member 18, which results in deformation of a clamping member 39, as well as radial movements of web portions 38 and mutual movements of clamping means 20a-20c (see FIG. 8 of WO'978). Eventually, all these movements result in clamping or unclamping of the covering sleeve 21 relative to the inwards facing threading 12d of the socketed pipe end 12c. In other words, a pivotation of the handgrip tool 45 in one direction brings the protector device in its locked condition, while a pivotation of the handgrip tool 45 in the opposite direction brings the protector device in its unlocked condition. Hence the protector device known from WO'978 has similarity with the protector known from the abovementioned document U.S. Pat. No. 2,238,643A in the sense that screw-threaded engagement of parts of the device has to be manually adjusted in order to realise the interchangeability between the locked condition and the unlocked condition. The locking structure of the device known from WO'978, however, is evidently much more complicated than that of U.S. Pat. No. 2,238,643A. Furthermore it is disadvantageous, both for the device known from WO'978 and for the device known from U.S. Pat. No. 2,238,643A, that, once these devices are in their locked condition, the tightened screw-threaded engagements may loosen, which results in the undesired circumstance that these known devices come loose from the pipe that is to be protected by them. Hence, in their locked conditions, these devices are not reliably fixed to the pipes. As will soon be apparent from the “SUMMARY OF THE INVENTION” and the “DETAILED DESCRIPTION” hereinafter, the protection device according to the invention solves these disadvantages. I.e., the protection device according to the invention has a simple locking structure providing ease and speed of manually installing and de-installing the device, while in its locked condition the device is reliably fixed to the wellbore pipe.
Another thread protector is disclosed in U.S. Pat. No. 4,379,471A. FIGS. 1-3 of U.S. Pat. No. 4,379,471A show that this known thread protector has a quite complicated locking structure. This locking structure comprises a wedge shaped locking member 30, up-bent tabs 18 and 20, and a tee tab lock member 36. A sharp object, such as the tip of a screw driver, must be employed to disengage the lock member 30 as shown in FIG. 2 of U.S. Pat. No. 4,379,471A.
Yet another thread protector is disclosed in U.S. Pat. No. 2,098,087A. Also this known thread protector has a quite complicated locking structure that requires the use of suitable tools for its operation.